0.78BiTi_0.1Fe_0.8Mg_0.1O₃-0.22CaTiO₃ Nanoscale-Thick Thin Films for Doping-Enhanced Electric Applications

Abstract

The high-quality (0.78-x)­BiTi0.1Fe0.8Mg0.1O3-0.22CaTiO3-(x)­Na0.5Bi0.5TiO3 nanoscale-thick thin films were prepared successfully on the Pt/Ti/SiO2/Si substrate via the sol–gel method. The influence of Na0.5Bi0.5TiO3 doping on the structure, topography, piezoelectricity, ferroelectricity, and dielectricity of BTFM-CTO-NBT thin films was investigated systematically. The X-ray diffraction and Raman results manifested that NBT doping induced the formation of the tetragonal phase, which existed between the rhombohedral and orthorhombic phases, and the elemental mappings revealed that the distribution of each element was uniform simultaneously. X-ray photoelectron spectroscopy analysis showed that NBT doping could effectively restrain the reduction of Fe3+, thereby reducing the oxygen vacancy concentration. The film had a minimum leakage current of about 3.19 × 10–10 A/cm2, a higher piezoelectric response, a maximum remnant polarization (2P r = 174.64 μC/cm2), and a relatively smaller coercive field (E c = 359.90 kV/cm) as x = 0.05. At the same time, the corresponding film had a maximum dielectric constant (469.6) and a minimum dielectric loss (0.063) at 1 kHz. These insights offer an alternative pathway to enhance the properties of BTFM-CTO thin films.